The Cook County Medical Examiner's office says 53-year-old Maryann Gurin was pronounced dead Thursday night at Palos Community Hospital in Palos Heights, shortly after she was brought there from the Kmart.
Gurin was being detained for allegedly trying to take clothing from the store when her breathing became labored and she collapsed, said Cmdr. Steven Vaccaro.
Two of Gurin's children, aged 18 and 14, were with her at the time, Vaccaro said.
"It's tragic," he told the Chicago Sun-Times.
Gurin's most recent address was not known, but she had lived in both Tinley Park and Orland Park in the past.